Interlocking receptacle, connecter, and cap



Dec. 21, 1937. H. HUBTBELL. JR

INTERLOCKING RECEPTACLE, CQNNECTER, AND CAP s Sheets-She et 1 Filed March 20, 1935 ATORNEYEE Dec. 21, 1937. H. HUBBELL. JR

INTERLOCKING RECEPTACLE, CONNECTER, AND CAP 42 INVENTO BY? .15 4 ATTORNEY$ Patented Dec. 21, 1937 2,102,625 m'rsnaocnmc nncaraactn, comvnc'rria,

' AND car I Harvey Hu'lb'bell, n-"- Bridgeport, Conn. Application March 20, 1935, Serial No. 11,942

6 Ciaima.

This invention relates to new and useful improvements in electrical devices and has particu lar relation to devices such as outlet receptacles, connecters and the like and the plug caps to be used therewith.

An object of the invention is to provide devices of the kind indicated, and including means whereby the plug cap when engaged with the receptacle or connecter is locked therewith against casual separation therefrom.

Another object is to provide devices such as receptacles, connectors and the like, and wherein an auxiliary tensioning spring is associated with each contact so that the resilient action of the contacts is not solely depended upon for the making of electric contact with the contacts of a plug. 1

Amongst the other objects is the providing of devices of simplified and sturdy construction whereby the devices will have long useful life even though subjected to abusive treatment.

Other objects and'advantages will become apparent from a consideration of the following detailed description taken in connection with the accompanying drawings wherein a satisfactory embodiment of the invention is shown. However, it will be understood that the invention is not limited to the details disclosed but includes all such variations and modifications as fall within the spirit of the invention and the scope of the appended claims.

In the drawings: Fig. 1 is a side elevational view with parts broken away and showing a receptacle con- 1 structed according to the present invention; together with the plug cap, and in'dotted lines suggesting the manner 10f connecting the receptacle and plug cap;

Fig. 2'is an end view of the'plug on a reduced scale; I I Fig, 3 is a front elevational view of thereceptac1e:. Y Y

Fig. 4 is .a rear elevational view of the receptacle; a

Fig. 5 is a rear elevational view of the body portion of the receptacle the rear plates being omitted;

Fig. 6 is a view partly in side elevation and partlyin section showing the invention as embodied in a connecter, with a side elevational view of theforward portion of the plug cap positioned to enter the connecter;

Fig. '7 is a pers ctive view on a reduced scale of the connecter and cap showing their proper (oi. ris -sac) relative positions just before inserting the cap into the connecter;

Fig. 8 is a. front elevational view of the plug cap;

Fig. 9 is a rear elevational view of the insulat- 5 ing mounting for the contacts of the plug cap removed fro the metal casin Fig. 10 is a front elevational view of the casing of the plug cap although except for a matter of length this same casing is used for the connecter;

Fig. 11 is a sectional view through the plug cap inner parts;

Fig. 12 is a sectional view taken substantially along the plane of the line l2-l2 oi. Fig. 6;

Fig. 13 is a front elevational view of the contact carrying portion of the connecter;

Fig. 14 is a view at right angles to Fig. 13 and with a portion broken away'to show the mounting of a contact;

Fig. 15 is a rear elevational view of the part shown in Fig. 13;

Fig. 16 is a rear elevational view of the body portion of the connecter with the auxiliary tensioning springs for the contacts in place therein;

Fig. 17 is an enlarged detail elevational view showing the arrangement of a. binding screw and contact terminal at the rear of the contact carrying portion of the connecter;

Fig. 18 is a detail sectional 'view taken substantially along the plane of the line Iii-l8 or Fig. 1'7;

Fig. 19 is a front elevational view of one of the auxiliary tensioning springs for the contacts of the receptacle and connecter; I

Fig. 20 is an edge elevational view of the spring;

Fig. 21 is a detail view showing the manner in which the contacts of the plug cap remain in engagement with the contacts of the receptacle or connecter during relative turning movement of the parts while connected; I

Fig. 22 is a view showing a portion of the receptacle in front elevation and showing the forward portion of the plug cap in transverse section and entering the receptacle, the dotted lines indicating the locked position; and I Fig. 23 is a view partly in section and partly in elevation at right angles to Fig. 22 and showing the locking engagement between the. plug cap and the receptacle. 7

- The present invention relates particularly to devices adapted for making detachable electrical connections, such for example as are used for connecting electric motors and other electrical devices to sources of current supply in garages 55 and factories, and includes a plug cap generally designated Ill and a socket which may be in the form of a wall receptacle generally designated ll (Fig. 1) or of a portable connecter such as is generally designated I2 (Fig. 6). 7 Referring in detail to the drawings and at first particularly to the receptacle I I, the same includes a body or block l8 of insulating material having an opening or bore 14 therethrough from front to rear, and having recesses I in the side walls of said bore. The forward end of each recess i5 is restricted by a shoulder l6 and (see Fig. 3) the entrance openings I I to three of the recesses from the front face of the receptacle are of one size while the entrance opening l8 to the other'recess is of a larger size. The shoulders l5 are laterally of the entrance openings l8 and are inwardly of the front ends of said openings.

Within each recess l5 and exposed through the open side thereof is a resilient metal contact blade l9 and such contact blades are carried by mounting portions 28 fitted in recesses 2|. in the.

rear surface of the block I .3. and each is equipped with a binding screw 22 for the connection of lead wires. One of the contact mountings designated 28a is of the ground contact, and secured to it by a rivet is a strap 23. The contact may also be provided with a binding screw 22a, but the binding screw is seldom used when ground strap 23 is used, as a wire is usually unnecessary when the ground strap is used. When strap 23 is not used the binding screw is used for connecting the ground wire. In each recess l5 at the rear side of each contact I8 is an auxiliary tensioning spring 24. Each of these tensioning springs comprises a piece of resilient metal, the

lower end portion of which is divided to provide legs 25 (Figs. 19 and 20) bent slightly out of the plane of the body of the piece, and at its upper end each spring is provided with a pair of lateral lugs 26 resting on the bottoms of recesses 26a in the insulating body l3. 5

When the springs 24 are in place their body portions are against the inner walls of the recesses l5 while their leg portions 25 are'against the forward or free end portions of the contacts i8 as shown best in Fig. l. The blades I! are connected with the mounting portion 28 by narrower necks 21, and the springs 24 being positioned as indicated serve to maintain the blades iii in their proper positions and prevent them for becoming set in a displaced position after repeated use.

A plunger and closure 28 is movable longitudinally in the bore i4, and ribs 28, 30, 3| and 82 projecting into the bore and extending longitudinally thereof serve to guide the plunger and hold it against any turning movement in the bore. The ribs 38 and 32 are provided with longitudinally extending grooves 33 which open through the rear face of the body l8 but are closed at their forward ends, and the plunger is provided with ribs 34 extending into said grooves, which ribs on engaging the closed forward ends of the grooves limit forward movement of the plunger. shoulders 35 to engage shoulders on the forward portion of the body just back of the front face thereof to limit movement of the plunger toward the forward side of the body. Ribs 36 of the plunger are shaped of the size of the entrances H to certain of the recesses l5, while the rib 3T of the plunger is of a size of the recess entrance I 8.

The plunger is normally held in a forward po- Also, the plunger may be provided with sition as in Figs. 1 and 3 closing the forward or entrance end of the bore l4. This is accomplished by means of a coil spring 88 the forward end of which is disposed in a socket 39 in the inner side of the plunger, and the rear end of which surrounds a projection 48 carried at the inner side of a plate 4| "disposed against the outer side of aninsulating closure plate 42. The latter has an opening therethrough for the passage of the projection 40, and screws 48 are passed through the two plates and through the body I! and are threaded into mounting clips 44,

which have slots 44a to receive screws for securing the lugs to the ears of a'wall outlet box (not shown)-and mount. the receptacle therein in the well known manner. One of the screws 43 (see Fig. 4) also passes through the strap 22 connected with the ground contact of the receptacle whereby this contact is thus grounded on the wall outlet box which is grounded in the usual manner.

As above suggested, instead of the socket being in the form of the wall receptacle II it may be in the form of a portable connecter such as generally indicated at I2 (Figs. 6 and '7). This connecter includes a forward body portion 45 of insulating material having a bore 48 therethrough corresponding with the bore 14 of the wall receptacle, and having the ribs 28, 88, ii and 32 projecting into the bore and extending longitudinally thereof. Also, the body 45 is provided with the recesses l5 corresponding in all respects with the recesses of the wall receptacle and each receiving one of the auxiliary tensioning springs 24 and resilient metal contacts 45 corresponding to the contacts I! of the receptacle H.

To the rear or inner end of the body 45 there is secured a section 41 including a disc-like portion 48 of insulating material from the forward side of which extends the contact blades 48 projecting into the body 45 and disposed in the recesses l5 thereof at the inner sides of the springs 24. An irregular block of insulating material comprising wings 58, 5|, 52 and 53 projects from the rear side of the disc 48, and terminal pieces 54 having lateral feet disposed in recesses in said side of the disc 48 are separated by said wings and are connected with the respective contact blades 48 as by rivets 55 (Fig. 14) passing through said terminal pieces and the disc 48. Each terminal piece 54 carries a binding screw 56, and the terminal pieces have their vertical edge portions received in notches 51 formed in opposing faces of the wings as shown best in Fig. 17.

In its rear surface the body 45 is provided with a locating notch 58 (Figs. 6 and 16) and on its forward face the disc 48 is provided with a locating lug 58. When the contact carrying member 41 is assembled on the body 45 with the contacts 49 in the recesses l5 the entrance of the lug 58 into the notch 58 insures that the parts are properly aligned. The disc 48 is provided with openings 50 which align with threaded metal inserts 8| in the body 45 whereby screws may be used to secure the parts together. One of the plungers or closures 28 is arranged in the bore 46 through the body 45 and may be moved longitudinally of said bore but is held against turning movement by the ribs 28, 28, 2| and 82 as will be understood. A coil spring 52 at its forward end enters the socket 39 in the plunger and at its rear end is disposed about a stud 68 carried by the disc 48 and bears against said disc whereby to normally maintain the plunger 28 in a position closing the forward end of the bore 46. One

of the blades 49 is the ground contact and its terminal element 53a, and has a laterally extending contact member 64 secured to itand disposed on the outer side of a cam-like thickened portion 85' of the disc 48, the member 64 being thus positioned to engage the inner surface of one ofshoulders 69 (Fig. 6) of casing 66 when the de vice is assembled therein and thus ground the contact on the casing.

The assembly comprising the body 45 and the contact carrying section 41 are mounted in a f metal shell or casing 66 (Figs. 6 and 7) the forwarcl portion 61 of which is cylindrical to accommodate the assembly and the rear portion 68 of which 'has opposite flattened sides to provide ahand. grip. The portions 07 and 88 are connected by shoulder portions 69, and when the above mentioned assembly is inserted into the shell, its-movement into the shell is limited by the shoulders 69 and the ground contact element 84 engages one of said shoulders while the peripheral edges of the body 45 and disc 48 are,

embraced by the forward cylindrical portion 81 of the shell.v In the rear orflatted portion of the shell there is secured an insulating lining 70 preferably of rigid moulded material, and the rear wall H of this lining and the rear wall I2 of the shell are provided with aligned openings 13 and I4 for the passage of a cord or cable I5 containing lead wires to the various binding posts 56. r

A relatively thick soft rubber pad I6, such for example as sponge rubber, is disposed at the inner side of the rear ,wall II of the lining l and is provided centrally with an opening -11 of such size that the cable 15 may be forced through it. This pad is held against the end wall H of the lining by the wings 50 through 53 above referred to as disclosed at the rear side of the disc 48. The pad serves as a seal to exclude dust, dirt and moisture from the interior of the connecter. In its outer surface the end wall of the lining I0 is provided with grooves 78 extending radially'from the opening Hand in each such groove is arranged an arm "I9 of an element 80 ofa cable clamp. These elements are L-shaped and the other arm 8i of each element extends outwardly through the opening I4 in the rear wall of the metal shell and such arms 8| are adjustably connected by screws 82 whereby the elements maybe clamped against the cord I5.

The plug I0 is for use with the described socket whether the socket takes the form of the wall receptacle II or the connecter I2 or any other desired form. Plug I0. includes a body portion 83fcornprising a relatively thick disc of insulating material, and projecting from the rear side of said body and integral therewith are lugs 84 the purpose of which will later more fully appear. A post 85 also of insulating material extends from the forward side of the body 83 and has one end clamped against said body as by a screw 88 passing through the post and body. Said end of the post bears against the central portion of the body, andabout-said central portion the body is provided with openings 81 through which extend the arms 88 of metal contacts 89 .each 'cut from piece of conducting metal and each at its inn r side having a dovetail 90 whereby when it is molded into the'post 85 it is securely interlocked therewith. If preferred a groove may be molded in the bakelite and the contacts slipped in'place'.

Contacts 89 extend radially beyond the outer I surface of the post 85 and each contact also includes an inner shoulder 9|, the purpose of which will later appear, and a shoulder 92" clamped in a notch in the forward face of the body 83 (see Fig. 11) on tightening of the screw 96. The arms or extensions 88 of the contacts each project between a pair of the lugs 84 and between said lugs eachsuch arm is provided with a binding screw 93for connection of lead wires of a cable II4 leading to a motor orother electrical device. A plug 94 of insulating material may be arranged to insulate the inner ends of the binding screws 93 from one another. From the foregoing-it is to be understood that the contacts.89 and 89aare moulded into the post 85 and are then with the post clamped to the body 837 on tightening of the screw 86. With this construction it will be apparent that the contacts are securely held in place 'and that a or casing 9'! when assembled therein and so the casing is grounded by this contact.

The assembly thus far described and shown particularly in Figs. 11 and 12 is to be mounted in an outer metal shell 91 comprising a forward substantially cylindrical portion 98 embracing the peripheral edges of the body 83 and a rearward portion 99 flattened on its opposite sides so as to be shaped for gripping. Theseportions 98 and 99 are connected by shoulders I00 and when the body and its contacts are assembled in the shell the conductor strip 95 from the ground contact engages one of the shoulders I00.

Within the flattened portion 99 of the shell there is secured one of the rigid moulded linings I0 described above in connection with the shell 68 of the connecter II, and this lining has the opening I3 in its end wall aligned with an opening l0! in the end wall I02 of the shell-91. A cord clamp comprising the elements 80 is mounted on the shell 91 as in the case of the shell 66. Further, within the lining 'II one of the soft or sponge rubber pads 16 is provided and is held in place by the lugs 84 extending from the rear surface of the body 83. Short screws I03 are passed through openings I04 in the body and threaded into tapped openings I in the shoulders I00 of the shell 91 whereby to secure the parts together.

Lug I06 on the lining on entering anotch I01 in the body 83 assures that the body is properly located within the shell. A similar lug I06 is used in the case of the connecter II and enters a notch I08 in the disc 48 of the contact carrying element 4I of the connecter. From the foregoing taken in connection with the drawings it will be understood that the only difference between the shells 66 and 91 resides in the fact 98 of the shell 91. The insulating linings 10 are the same in each case as are the cord clamps of a cross but may be of other shapes, and in its forward end the post-like portion of the plug is provided with a similarly shaped recess H8. Also, the post 85 is provided with a longitudinally extending groove III of a depth and size to accommodate the longitudinally extending rib 28 which projects into the bore of each socket. This groove III is wider than rib 28 so as to permit a limited turning movement of the cap in the receptacle and the connecter. Further, on the forward face of the body portion 83 of the plug there is an indicating mark H2 which may be of a color contrasting with the color of the body and a similar mark H3 is provided on the forward face of each socket.

Assuming that the various contacts of the devices each have a lead wire connected with them, when it is desired to connect the plug ID with either of the sockets H or l2 the forward end of the post 85 of the plug is placed against the forward face of the plunger 28 with the cross shaped recess I I out of alignment with the cross shaped projection ted lines in Fig. 3. The positions are well shown in Fig. 7. The arrangement is such that the projection ill! and the recess H must be out of alignment in order that the post 85 of the plug and the contacts on said post may enter the bore of the socket. That is, when the projection and recess are crossed as suggested in Fig. 3'the large ground contact 89a of the plug is in alignment with the enlarged recess entrance l8 of the socket and the groove III in the post of the plug is aligned with the projection or rib 28 of the socket. Therefore, with the parts correctly relatively positioned the post portion of the plug may be forced into the socket by a longitudinal movement and this action will result in the plunger 28 being forced inwardly against the action of the coil spring 38 or 82 which normally holds it in its forward position closing the bore of the socket.

As the plug is pushed into the socket the contacts 89 and 88a of the plug engage those ([9 or 48) of the socket, and when the plug is within the socket to the extent the plug contacts are inwardly with respect to the shoulders It at the outer ends of the recesses l5 of the socket the plug and socket are rotated relatively tocarry the shoulders 92 of the plug contacts over the shoulders l6 of the socket. Thereafter, .on the plug being released the action of the coil spring 38 or 62 forcing the plunger 28 against the plug presses the shoulders 92 of the plug contacts against the shoulders l8 of the socket. The mentioned turning movement between the plug and socket also causes the recess H0 in the end of the plug to align with the prol'ection I89 on the forward face of the plunger and such projection enters such recess since the plunger is being forced forwardly by the coil spring. This interlocking engagement between the plug and plunger prevents casual turning of the plug relative to the socket in a direction to carry the plug contacts away from the socket shoulders l6 and into alignment with the entrance openings and 18 for the plug contacts.

From the above it will be understood that the plug contacts engage the socket contacts as the plug is pushed into the socket and that such contacts remain in engagement during the relative turning movement of the plug and socket. Also, this relative turning causes an interlocking of the plug and socket since the shoulders 8| of the plug contact are by the turning movement disposed over the shoulders 18 of the socket so that the plug and socket cannot be separated by I88, as suggested by the dotthat the shoulders 8| of relative longitudinal movement. To withdraw the plug from the socket the parts must be turned relatively in the opposite direction to again align the plug contacts 88 and 88a with the entrances or openings l1 and I8 to the socket and the spring pushing the plunger forwardly will eject the plug from the socket. When the shoulders 9| of the plug contacts are in position overlapping the shoulder I8 of the socket the projection I09 of the plunger being held in the recess H0 in the forward end of the plug casual turning movement of the plug in the socket in a direction to release the plug is prevented, andthe plug is thus locked in the receptacle or connecter against casual separation in use. As the side walls of the ribs 18 and grooves 8 are inclined they do not prevent reverse turning movement of the plug by forced operation of the operator when it is desired to remove the plug from the receptacle or connecter. In this operation these-inclined walls have a, camming action to force the plunger 28 inwardly to remove the ribs I09 from grooves llll.

With special reference to the connecter l2 and the plug l8 it is noted that these parts are so constructed that the flattened outer end portions in a measure serve .to indicate when the plug and connecter are properly aligned so that the plug may be pushed into the connecter. When these flattened outer end portions of the plug and connecter are in substantial alignment with one another the plug may be pushed into the connecter after which it is given a partial turn to bring about the above described interlocking of the parts.

With either socket when the indicating mark 2 on the plug is aligned with the indicating mark H3 on the socket the parts are correctly positioned for the plug to be pushed'into the socket. Fig. 21 indicates the manner in which the plug contacts engage thesocket contacts on initial movement of the plug into the socket and during the turning movement to render eifectual and ineffectual the interlocking of the plug and socket. In Fig. 22 the full lines indicate the plug entering the socket and the dotted lines indicate the'sho'ulders of the socket with which the plug will interlock after the relative turning movement above referred to.

Fig. 7 shows the plug and connecter in proper position for insertion of the plug or cap in the connecter. As the enlarged contact 89a cannot enter any of the grooves l1 but only the groove l8 it will be evident the plug can be inserted only so that all the contacts on the plug engage the proper contacts in the receptacle or the connecter. However, mechanics using the device have been known to grind down the large contact 88a so the plug could be inserted in other positions with consequent ruination of the apparatus. To obviate this the rib 29 is provided in the receptacle and connecter with the longitudinal groove I II in the plug to receive it. The plug can thus be inserted only when rib 29 is in the groove Hi. This groove is made sulficiently wide to permit the limited turning movement of the plug to the locking position after it has been inserted in the receptacle or connecter.

Although a four wire device is shown and described the same construction and arrangement can be used for two and' three wire devices.

Having thus set .forth the nature of my in vention, what I claim is:

1. In an electrical device, a socket, a plug, said socket comprising a body of insulating material -'closing the forward end of said bore, shoulders having a bore therein and recesses at the sides of said bore and opening through the front end of the body, contacts in said recesses and extending lengthwise of the body, tensioning springs in said recesses in the rear of. the contacts and bearing against the walls of the recesses and the forward end portions of the contacts, laterally extending lugs on said springs, said body having locating recesses receiving said lugs to position said springs, and contacts carried by said plug and engageable with the first contacts on insertion into said bore.

2. In an electrical device, a socket, a plug, said socket comprising an insulating body having a bore therein and contacts at the sides of the bore, a plunger reciprocable in the bore and held against turning therein, a spring normally maintaining the plunger in position closing the forward end of the bore, contacts on the plug and engageable with the first contacts on insertion of the plug into the bore by forcing the plunger inwardly against the action of the spring, said plug and body'adapted for limited relative turning movement, interlocking means to prevent separation of the socket and plug by a longitudinal movement and mounted to become effective by a relative turning of the plug and socket in one direction, and cooperating means on the plug and plunger and thereafter preventing casual relative turning movement of the plug and socket in the opposite direction.

3. In an electrical device, a socket, a plug, said socket comprising an insulating body having a bore therein and contacts at the sides of the bore, a plunger reciprocable in the bore and held against turning therein, a spring normally maintaining the plunger in position closing the forward end of the bore, contacts on the plug and engageable with the first contacts on insertion of the plug into the bore by forcing the plunger inwardly against the action ofthe spring, said plugand body adapted for limited relative tuming movement, interlockingmeans to prevent separation'of the ,sbcket and plug by a longitudinal movement and mounted to become eifec'-' socket comprising a body of insulating material having a bore and contacts at the sides of said bore, a, plunger movable longitudinally in said bore and held against turning therein, a spring normally maintaining said plunger in position locking relation by said relative turning of the plug and socket to thereafter prevent casual relative turning of the plug and socket. I

5. In an electrical device, a socket, a plug, said socket comprising an insulating body having a bore therein and contacts at the sides of the bore, a plunger reciprocable in the bore and held against turning therein, a' spring normally maintaining the plunger in position closing the forward end of the bore, contacts on the plug and engageable with the first contacts on insertion of the plug into the bore by forcing the plunger inwardly against the action of the spring, interlocking means to prevent separation of the socket and plug by a \lon gitudinal movement and mounted to become effective by a relative turning of the plug and socket in one direction, interlocking means on the forward face of the plunger and the forward end of the plug to resist relative turning movement of the plug and body and comprising a projection on one of said members and a recess, in the other member means whereby the plug may be inserted into said bore only when said projection and recess are out of alignment whereby as the plug and socket are turned relatively to render said first interlocking means effective the projection and recess are aligned and the spring forces the plunger toward the plug to have the projection enter the recess and hold the plug against casual turning movement relative to the socket.

6. In an electrical device, a-socket comprising an insulating body having a bore therein and contacts adjacent the bore, a plunger and closure for the bore reciprocable therein and held against turning movement, a spring normally maintaining the plunger in position closing the forward end of the bore, a plug insertable in the bore and having contacts engageable with the first contacts, said socket and plug having means to lock the plug in the socket on relative turning movement of the plug in one direction, andcooperating separable means on the plunger and plug holding the plug against casual turning movement in the opposite direction.

HARVEY HUBBELL, JR. 

